verify_rescue_musig added to EddsaSignature

[StanislavBreadless]

Added rescue musig verification that adds constraints to the constraint system and a test that shows that it works properly.

Also I added some utilities without which the verification algorithm wouldn't work,

[burdges]

I'm curious: What doers this do?

[shamatar]

This is a backport from zksync for MuSig with Rescue as a hash function, but it doesn't look proper yet. In any case, this is work of our summer interns and will be reviewed.